1. Field of the Invention
The present invention relates to a housing base utilized in a recording medium drive such as a hard disk drive, HDD, for example.
2. Description of the Prior Art
An actuator arm is incorporated within a hard disk drive so as to support a head slider at the tip end. A voice coil motor, VCM, is coupled to the actuator arm. The voice coil motor includes a pair of permanent magnets and a voice coil. The permanent magnets are fixed to a housing base of the hard disk drive. The voice coil motor is located in a space between the permanent magnets. The voice coil generates a magnetic flux in response to supply of electric current. The generated magnetic flux interacts with the magnetic flux of the permanent magnets so as to induce the swinging movement of the actuator ann. The head slider is thus allowed to be positioned at a target recording track on a magnetic recording disk.
The intensity of the magnetic flux should be enhanced to improve the performance of the voice coil motor, for example. The magnetic flux may leak outside the housing base around the voice coil motor. The leakage of the magnetic flux is preferably prevented to the utmost. In particular, a printed circuit board is attached to the outside of the housing base in the hard disk drive. A controller circuit is established on the printed circuit board so as to control the operation of the hard disk drive. If a metallic piece or dust moves closer to the printed circuit board in response to application of the leaked magnetic flux, the metallic piece may cause a short on the printed circuit board.